The Changing State of Breathing During Inhalation of Co2, Studied With an Inexpensive, Recording Co2‐analyzer

A method is described for recording alveolar CO2 tension using simple and inexpensive apparatus. The changing state of hyperventilation due to CO2 has been studied and a procedure devised for deriving the steady‐state CO2‐response line from data obtained during the changing state. This procedure has considerable practical advantages over conventional methods. Evidence is presented to show that the time needed for equilibration of CO2 between the arterial blood and the cells of the respiratory centre is of the order of 4 min.